Fuse



Sept. 18, 1956 Filed Jan. 22, 1952 FIG. l

H. RUEGER FUSE 2 Sheets-Sheet 1 INVENTOR HERMAN RUEGER ATTORNEY Sept. 18, 1956 RUVEGER 2,763,213

FUSE

2 Sheets-Sheet 2 Filea Jan. 22, 1952 IN VEN'I'OR HERMAN RUEGER BY I ATTORNEY United States Patent Pa., assignor to the United States of America as represented .by the Secretary of the Army Application January 22, 1952, Serial No. 267,633 4 Claims. (Cl. 102.84)

This invention relates to a mechanical fuse of the type which is independently powered by a spring and which depends upon the firing of the shell for the start of operation of the timing mechanism.

The object of the present invention is to provide a timing mechanism which can be varied from of a second to 45 seconds and at & second intervals, which will withstand extremes of temperature operation and which will be reliable, accurate and relatively inexpensive.

A further object of the present invention is to provide a mechanical timing mechanism which consists principally of tiers of planetary gear systems arranged around a single center arbor which serves both as an arbor and as a firing pin, with the firing pin so arranged that it may be operated either by impact or by release through predetermined arrangement of the timing gears.

It is a further object of the present invention to provide a mechanism, certain parts of which should it become necessary can be assembled in the darkness by sense of touch.

A further object of the present invention is to provide a mechanism which is assembled using as many duplicate parts as possible to provide ease of manufacturing and assembling.

The invention is shownin the accompanying drawings in which:

Figure 1 is a cross section of the nose of the shell showing the timing release mechanism.

Figure 2 is a perspective view of the pawl and ratchet mechanism together with a single plate containing the planetary gears, and a plate showing the central spur gear.

Figure 3 is a detail view showing the attachment of I the mainspring with the central arbor.

Figure 4 is a detail of a safety plate.

Figure 5 is a detail of one form of escapement.

Figure 6 is a detail of the setting ring showing the graduations.

. Figure 7 is a detail of the mainspring and extensible rotating cross arm.

Referring particularly to Figure l, a shell casing 10 is formed with threads 11 at its open end to receive a circular housing12 which serves as a support for the entire timing mechanism. The housing 12 is formed with diametrically opposite holes 13 to receive bolts 14 on which the timing mechanism is supported. The housing 12 is also formed with an upper circular compartment 15 in which is located a mainspring 16. A timing ring 17 is supported on a plate 18 which is carried by the housing 12 and in turn is formed with an escape hole 19 and a restraining pin 21). A central arbor and firing pin combined 21 passes through the center of the ring 19 and the housing 12 and is formed with a slot 22 by means of which the mainspring is engaged.

A collar 23 is secured to the inner end 24 of the mainspring 16 by a stud 25. The stud 25 is bored at 25 to receive the pin 25" which is permanently affixed to the collar 23. The pin 25" prevents withdrawal of the stud 25 except by vertical upward movement. The stud 25 functions as an anchor for the inner end of the mainspring and as a key to translate rotative movement between the arbor 21 and the pawl 27 while permitting limited vertical movement of the arbor 21.

The collar 23 which attaches the mainspring to the arbor through the stud 25 passes through the plate 26 and has secured to its lower end a multifingered pawl 28. This pawl is formed of spring material and has three groups of four fingers each which are directed outwardly to angular contact with the ratchet teeth 29 of the ratchet gear 27. The twelve fingers of the pawl 28 are cut to length in groups of three, giving three fingers of the same length spaced every fourth finger making it possible to provide four times as many stopping places as there are teeth, should said teeth be engaged by a single pawl or pawls of equal length. The ratchet gear 27 is formed with a central plate 30, an upper plate 31 and a lower plate 32, the plate 32 having gear teeth 33 which are engaged by the planetary gears 34 carried by the plate 35 which is held stationary by the bolts 14. The planetary gears 34 engage the central spur gear 36 which transmits its rotation to the ring gear 37 to be in turn engaged by other planetary gears similar to those shown at 34.

At the end of a sequence of planetary gears and ring gears, a safety plate 38 is inserted. The plate is formed with a single planetary gear 39 and a gear segment 40 which is formed with a hole 41. At the start of the rotation of the gear system the gear 39, rotating in the direction of the arrow, turns the gear segment 40 so that the hole 41 is in alignment with the center hole 42 placing the arbor 21 or striking pin 38 in operative position. A reduced portion 43 of the gear segment 40 allows rotation of the planetary gear 39 and holds the segment 40 in proper position.

Located immediately above the safety plate 33 is an escape plate 44 carrying an escape gear 45 which is attached to the gear 39 by the arbor 46. This arbor also carries one of the planetary gears 34 which is imme diately above said escape gear and the gear 39 which is immediately below said escape gear. A substantially U-shaped escape disc 47 having a pair of opposing teeth 48 is pivoted at 49 to the escape plate 44 and adapted to oscillate so as to engage first one tooth and then the other with the gear 45. Regulation of the escape disc 47 by increase or decrease of its mass or by springs (not shown) will govern the speed of escapement.

The entire assembly of planetary gears and ring gears together with mainspring, the pawl, the escapement and the safety plate are positioned on the bolts 14 which are supported by the housing 12.

A bottom plate 50 is carried by the bolts 14 and immediately underlies the fuse mechanism. This plate is formed with a central opening 51 in which is mounted an explosive cartridge 52 directly in the path of movement of the arbor 21.

The arbor 21 extends upward into the very nose of the shell to be journalled by sleeve 53 and terminate in contact with a button 55 which covers the end of the arbor and forms the nose of the shell. A felt washer 54 serves as a friction disc to hold the arbor against displacement during assembly.

The arbor extends through a central supporting web 56 located in the nose 10' of the shell and formed with a series of holes running at an angle and intersecting the central opening housing the arbor. Slidably mounted in the holes of the web member 56 are a series of plungers which may be termed for convenience an initial plunger 57, outward moving secondary plungers 58, inward moving secondary plungers 59 and release plungers 60. Pinned to the arbor 21 is a collar 61 which is engaged by the release plungers 60, holding the arbor in inoperative position.

Patented Sept. 18, 1956 Located between the mainspring 16 and the web 56 is the timing ring 62 having indicia 63 engraved on its outside surface and formed with sharp teeth on its lower outside edge. A ring of soft metal 64 underlies this timing ring and receives the points of the teeth when the inertia of the setting ring caused by the firing of the shell causes the teeth to be pressed back against the ring of soft metal. Screws 65 engage the hole 66 in the ring 17 so that turning of the setting ring 62 will move the ring 17 with the escape hole 19 therein to a predetermined angular distance from the nose piece 70 which will determine the time the fuse mechanism will run.

Mounted on the arbor 21 and adapted to rotate within the ring 17 is an extensible cross arm 67. This extensible cross-arm is formed in two parts and is a parallel sided segment of a circle divided near the center and cut to accommodate the arbor. A pair of springs 68 mounted on rods 69 tend to force the rear sections of the extensible cross arm away from the arbor and the two sections of the extensible cross arm away from each other and into contact with diametrically opposite areas of the inner side of the ring 17. The arcuate shaped end of the larger section of the extensible cross arm is formed with a rectangular nose piece 70 which contacts the wall of the grooved lower part of the ring 17 until it reaches the rectangular opening 19.

The two sections forming the entire shell are assembled separately with the Web 56 held in the nose by a bottom plate 71 which is secured to the shell by screws 72; Previous to the assembly of the nose and the body portion of the shell, the web is assembled by fixing the plungers in position as shown in Figure 1 with the two release plungers 60 hearing against the collar 61 and positively supporting the arbor or plunger 21. Only one set of the plungers includes an initial plunger 57. The set shown on the left of the web in the drawing is only an additional safeguard which is released by inertia upon the firing of the shell. This safeguard is added to prevent possible mishap should the shell be dropped or mishandled in any way. The arbor or plunger 21 is mounted in the bearing 53 with the felt washer 54 having suflicient friction with the nose of the shell to support the arbor in desired position during assembly. The plungers are then assembled in the web and locked in position by the split ring 73 and the web placed in position with its nose 74 engaging the bearing 53. A thimble 75 having a compression spring 76 is previously placed in position around the arbor and into the web and held in place by a plate 77 secured by screws 73. With the web in position the plate 71 is screwed on the nose of the shell.

The lower portion of the shell receives the mechanical timing element consisting of the planetary gears and ring gears, the mainspring and ratchet and the extensible cross arm mechanism and timing rings for releasing the initial plunger 57 and plungers 58, 59, and 60, and arming the shell.

As a subassembly the planetary gears and ring gears are assembled with the safety plate 38 having the safety gear segment 40 placed in lowermost position directly above a bottom plate 50 which may or may not be included at this time. The bottom plate 50, here shown carried by the bolts 14, may be mounted separately or may be mounted differently from the manner illustrated. Directly above the safety plate is carried the escape plate 44 having the escape disc 47, while above that an assembly of four sets of the planetary and ring gearing shown in Figure 2 is mounted. Carried above the topmost of these four sets is the ratchet wheel 27 which underlies the housing carrying the mainspring. The

extensible cross arm mechanism is slipped over the arbor and the entire timing assembly is positioned so that the arbor is directly above the safety plate 38 and almost in contact with the segment 40. The extensible cross arm is set up in its initial position with the nose 70 in 4 contact with the pin and the initial plunger in contact with a sleeve 79 formed with an upper cross arm. 80 and connected to the arbor 21 through a slot 81 and a pin 82. Posts 83 and 84 engage" the cross arm 80 and transfer the turning of the arbor through the pin 82 to the extensible cross arm 67, during the winding of the mainspring, and its rundown, later.

With the nose assembly and the casing assembly in 1 position the two parts are brought together, the lip of the plate 71 being formed with an inner circumferential groove 85 coinciding with an outer circumferential groove 86 formed on the timing ring 62. A crimped wire ring 87 fits in the groove to interlock the nose of the shell with the casing. This ring holds the nose of the shell secure to the casing but permits turning of the timing ring 62 for setting the timing mechanism.

In the operation of the shell and assuming that the plungers are in the position shown in Figure 1, the nose is grasped and rotated in relation to the casing. The initial plunger 57 rotating withthe noseengages the cross arm 80 and turns the sleeve 79 and the extensible cross arm 67 until the nose 70 engages the pin 20. This completes the rotation of the pointer independently of the rest of the mechanism. At the same time the pin 82 turns the arbor 21 and through the pin 25 winds the mainspring 16. Winding the mainspring 16 causes rotation of the ratchet, which due to its peculiar construction engages at practically aninfinite number of points so that there is absolutely no backlash during the winding period. Rotation of the nose for 3 /2 turns will completely wind the mainspring and the shell is ready for the timing ring to be set at desired position. By turning the ring 62 and observing the indicia 63 with relation to a zero setting 88 on the nose, the ring 17 is moved to position the hole 19 in relation to the nose 70 of the extensible cross arm 67,. so that the movement of the extensible cross arm 67 upon the starting of the mechanism is clockwise from its angularly set position until it comes opposite the hole 19.

The firing of the shell causes the plungers 58 to move downward against their respective springs and to release the plungers 59 and in turn and permit their downward movement, thus relieving the arbor at the collar 61. The plungers cannot return to their former positions once released, because of the springs behind 58 and spring 76. The downward motion of the plunger 58 permits an up- Ward motion of the plunger 57 due to its compressed spring, thus releasing the cross arm 80 of the sleeve 79 and permitting rotation of the sleeve due to the power of the mainspring. With the rotation of the sleeve the extcnsible cross arm 67 moves from its preset angular position clockwise until it comes opposite the opening 19, which distance has been determined by the setting of the ring 62. To control the rotation of the arbor 21 the series of planetary gears and ring gears is rotated through the pawl and ratchet mechanism which is connected directly to the mainspring. At the start of rotation of the planetary gear system, the gear 39 rotates and moves the safety segment 40 to bring the hole 41 above the opening 42 and thus clears the way for the downward movement of the arbor 21 into contact with the cartridge 52. Referring back to the extensible cross arm 67, the nose enters the hole 19 and permits the portion of cross arm 67 adjacent to nose 70 to move radially outward from the arbor 21 permitting a downward motion of the sleeve 79 and a subsequent downward motion of the arbor 21. The shell may also be exploded by the nose coming in contact with any soiid resistance by forcing the plunger downward, irrespective of whether the timing mechanism has completely functioned or not as the safety segment is moved out of position with the passage of the first half second. Until the spring has been wound, the sector 40 will not be caused to move from its initial safeguarding position, and until the shell is fired the release plungers will not permit the arbor shoulder 61 to be pushed rearward by any accidental blow on the shell nose or otherwise.

What is claimed is:

1. A shell fuse for timed or impact release, comprising a central arbor forming the impact rod, means for bolding said arbor in inoperative position prior to the firing of said shell, means'for releasing said holding means upon the firing of said shell, a mechanical timing mechanism including a mainspring attached to said arbor, a transversly divided extensible cross arm mounted for rotative and radial movement, spring means normally urging the parts of the pointer away from each other, means for determining the radial movement of said extensible cross arm, said pointer in normal position forming a secondary holding means for said arbor, the radial movement of said extensible cross arm serving to release the two parts of said extensible cross arm causing separation to release said arbor.

2. A shell fuse for timed or impact release, comprising a central arbor serving as an impact rod, one end of said arbor projecting into the nose of the shell, the other end of said arbor being adapted to engage an explodable cartridge, means for holding said arbor in inoperative position prior to the firing of said shell, means for releasing said holding means upon the firing of said shell, a timing mechanism, said timing mechanism being started upon the release of said arbor holding means, means for governing the rate of rotation of said timing mechanism, a transversly divided extensible cross arm being connected with said timing mechanism to rotate in synchronism therewith and serving as a secondary stop for said arbor, said extensible cross arm being mounted for rotation and radial movement, means for controlling the radial movement of said extensible cross arm relatively to said arbor, said radial movement releasing said arbor for impact upon said cartridge.

3. A shell ifuse for timed or impact release, comprising a central arbor, a timing mechanism substantially concentric with said arbor, said timing mechanism comprising a mainspring, means for Winding said mainspring, a ratchet for normally holding said mainspring in wound position, a plurality of gears connected to said ratchet, an escape mechanism connected to said gears for limiting the rate of rotation of the timing mechanism, a transversely divided extensible cross arm rotated by said arbor under the influence of said timing mechanism, said extensible cross arm moving radially when in a predetermined angular position, a ring having an escape notch for determining the radial movement of said extensible cross arm, a primary holding means for said arbor released upon the firing of the shell, said extensible cross arm forming a secondary holding means for said arbor and released upon the radial movement of said extensible cross arm to permit longitudinal motion of said arbor. 4. A timing mechanism for a mechanical lfuse, comprising a central arbor serving as an impact rod, a mainspring, means for attaching said mainspring to said arbor to provide for rotative movement and limited longitiudinal translative movement, a sleeve having radial arms fitting over and keyed to said arbor, a transversely divided extensible cross arm overlying said sleeve and serving as a stop for longitudinal translative movement of said arbor, said sleeve arms engaging said extensible cross arm to provide rotary movement to said extensible cross arm, a ring formed with an escape notch about said extensible cross arm, said extensible cross arm being springurged against the inner side of said ring, said rotative movement of said extensible cross arm bringing said extensible cross arm opposite said escape notch to permit radial movement of said extensible cross arm, said radial movement releasing said sleeve and said arbor to permit longitudinal translative movement of said arbor.

References Cited in the file of this patent UNITED STATES PATENTS 1,393,585 Sutton Oct. 11, 1921 2,369,310 McGrath et a1. Feb. 13, 1945 2,398,439 Middlemiss Apr. 16, 1946 2,421,271 Kiang May 27, 1947 2,446,745 Delay Aug. 10, 1948 2,452,562 Gillette et a1. Nov. 2, 1948 FOREIGN PATENTS 338,081 Germany June 14, 1921 

